Short- and long-term impacts of PIT

tags on hatchery Fall and Spring

Chinook salmon

Curtis Knudsen1, Steve Schroder2, Mark Johnston3,

Todd Pearson2 and Dave Fast3

1Oncorh Consulting

2Washington Department of Fish and Wildlife

3Yakama Indian Nation

In-river Survival of PIT

Tagging Hatchery Fall Chinook

________________________________

Effects of PIT Tags on Smolt-to-Adult

Recruit Survival, Growth, and Behavior of

Hatchery Spring Chinook Salmon

In-river Survival of PIT

Tagging Bingham Creek

Hatchery Fall Chinook

Curtis Knudsen and Steve Schroder (WDFW)

Acknowledgments

• Debbie Frost (NOAA/NMFS) PIT tagging

• Earl Prentice (NOAA/NMFS) provided PIT

tags

Olympia

Chehalis R

N

W E

S

Purpose: Compare PIT tagged fish survival rates to

Control group survival rates

– PIT tagged group

– Two control groups

• Unhandled Control

– During tagged left undisturbed

• Handled Control

– Netted, transferred, and anesthetized without being

marked

Two releases of each - a total of 6 groups

released

Ambient water

Eggs within each of

the 6 trays developed

unique otolith codes

Chilled Water 4°C

Taken from: http://npafc.taglab.org

Wa

ter

tem

p

Time (days)

1,100 fry

1,100 fry

1,100 fry

1,100 fry

Hand count

2 m circular tanks

Randomly assigned tanks to treatment and control groups

Fish Length At Tagging

• Fish averaged 75-78 mm at the time of PIT

tagging (sd=4-5 mm)

• No fish less than 60 mm were PIT tagged

• Fish were reared for additional 3-5 weeks before

replicate releases were made separated by 2

weeks

Mean Fork Length +1 sd at Release

65

70

75

80

85

90

PIT1 PIT2 Con H1 Con H2 Con U1 Con U2

65

70

75

80

85

90

PIT1 PIT2 Con H1 Con H2 Con U1 Con U2

Len

gth

(m

m)

• Fish were reared for additional 3-5 weeks before

replicate releases were made separated by 2 weeks.

• Fish were trucked to a release site 21 km above a

juvenile fan trap on Bingham Creek.

• The trap was operated over the next 3 months,

checked twice daily.

• All recaptures were sacrificed and the otoliths

decoded to Con/Trt and Release groups.

• All captured fall chinook were part of our study.

Bingham Creek Fan Traps

PIT Tag Loss From Recaptures

• First release group lost 2.0% of their PIT

tags

• Second release had no tag loss

% d

evia

tio

n f

rom

Co

n U

Mean = -23.3%

X2-test p <0.05

Mean and Range of Survivals Relative to Control

Unhandled Group Over First and Second Releases

-30

-20

-10

0

10

Con U Con H PIT

Mean = -0.5%

X2-test p >0.05

Conclusions

• Marked fish were held long enough to recovery from general handling stress (ConU=ConH post-release survival)

• PIT tag loss was <2% over the 90 days trapping

• PIT tagged groups showed significantly higher post-release mortality (mean 23%) relative to the Control Unhandled group over the 90 days of trapping

Effects of PIT Tags on Smolt-to-Adult

Recruit Survival, Growth,

and Behavior of Hatchery Spring

Chinook Salmon

Knudsen, C., M. Johnston, S. Schroder, W. Bosch, D. Fast and C.

Strom. 2009. Effects of Passive Integrated Transponder Tags on

Smolt-to-Adult Recruit Survival, Growth, and Behavior of

Hatchery Spring Chinook Salmon. NAJFM 29:658–669.

Acknowledgments

• Tagging of juveniles and recovery of adults was

by Yakama Nation personnel

• BPA for providing the funding through the YKFP

Monitoring and Evaluation Program

Study Design

• Double tag (PIT and snout CWT) approximately 40K juvenile spring chinook in October-December

• Held for 1.5 additional months and volitionally released from March 15-May 30

• Repeated over 5 years (releases in 1999 to 2003)

• All hatchery origin adults (ages 3, 4 and 5) were interrogated for tags at Roza adult trap (April-Sept.) sampled for length, weight, and age (scales)

• SARS and tag loss were estimated based on recapture data by broodyear

Easton Acclimation

Jack Cr. Acclimation

Clark Flat Acclimation

Cle Elum Hatchery

Roza Adult

Monitoring Facility

Yakima Basin

Broodyear

Juvenile Releases 1997 1998 1999 2000 2001

PIT/CW tagged 39,892 37,385 38,791 37,580 40,020

Non-PIT (marked) 346,156 552,298 719,998 796,705 334,358

Total released 386,048 589,683 758,789 834,285 374,378

Fish ladder

Roza Adult

Monitoring

Facility

pitrP̂ = [Probability of losing a PIT tag])( ,cwtpitcwt

cwt

RR

R

1

cwtrP̂ = [Probability of losing a snout CW tag])( ,cwtpitpit

pit

RR

R

1

0%

1%

2%

3%

4%

5%

6%

7%

8%

1998 1999 2000 2001 2002 Mean

Brood year

Percen

t ta

g l

oss

PIT

CW

Juvenile tag loss rates before release

1.9%

3.7%

Not in the

study

Adult PIT and CW tag loss rates

0%

5%

10%

15%

20%

25%

1997 1998 1999 2000 2001 Mean

(+95% CI)Brood year

Per

cen

t ta

g l

oss

PIT

CW

6.7%

18.4%

p<0.01

Roza PIT tag recovery efficiency estimates

Recovery

year

NOAA carcass

PIT tag

recoveries

PIT tags

observed

at RAMF

% observed

at RAMF

2002 13 12 92.3

2003 9 9 100.0

2004 10 10 100.0

2005 2 2 100.0

2006 8 8 100.0

2007 2 2 100.0

Total 44 43 Mean 98.7

Data provided by Andy Dittman, NOAA

2 3 4 5

Age (years)

0.0

0.2

0.4

0.6

0.8

Arc

Sin

(T

ag l

oss

)0.5

PIT tags

CW tags

PIT r2 = 0.191, p = 0.382, n = 18

CW r2 = 0.169, p = 0.445, n = 18

1

,, ))((1

cwtpitpitcwtpitcwt

pitcwt

RRRR

RRc

)(ˆ,cwtpitpitcwt RRRcR

From: Seber. 1982. The estimation of animal abundance

R̂ is the number of recaptures corrected for tag loss

(Joint probability of losing both PIT and CW tags)

Uncorrected Non-PIT SARS = (# Non-PIT recoveries)

(# Non-PIT released)

Uncorrected PIT SARS =

Corrected Non-PIT SARS = (# Non-PIT recaps - Est PIT/CW tag lost )

(# Non-PIT released)

leased

pitcwtpit

PIT

RR

Re#

Corrected PIT SARS = /(#PITReleased)Rpitˆ

SARS Corrected for PIT Tag Loss

NonPITeffect SARS[(1-PIT )* ] + ε

Linear model of PIT tag effect:

PITSARS

Regressed SARSNonPIT vs SARSPIT and the

slope is an estimate of (1-PITeffect )

0.00

0.01

0.01

0.02

0.02

0.03

0.000 0.005 0.010 0.015 0.020 0.025

SARSNon-PIT

SA

RS

PIT

Corrected for PIT tag Loss

SARPIT = 0.897 * SARNon-PIT

95% CI = 0.851 to 0.944

r2 = 0.997, p<0.001

1:1

Correct for tag loss

Uncorrected

Uncorrected

SARPIT = 0.750 * SARNon-PIT

95% CI = 0.713 to 0.787

r2 = 0.997, p<0.001

• PIT Tag Loss + Mortality → 25% mean reduction in

adults SARS

• PIT tag mortality → 10% mean after correcting for

PIT tag loss

1997 1998 1999 2000 2001

130

140

150

160

170

Med

ian

RA

MF

Da

te

No PIT tag

PIT tagged

- Mann-Whitney

All p > 0.09

- No consistent

trend over brood

years

Median Date of

Passage at Roza

Adult Monitoring

Facility

Age 4

50

55

60

65

1997 1998 1999 2000 2001

No PIT tag

PIT tagged

Mea

n P

OH

P l

eng

th (

cm)

+ 1

sdMean POHP Length

• All comparisons

PIT<Non-PIT

• Only Age 4 signif-

icant; mean 1.1 cm

• 2-way (Tag x BY)

ANOVA

Tag effect p = 0.024

Age 4

No PIT tag

PIT tagged

3

4

5

6

1997 1998 1999 2000 2001

Mea

n b

od

y w

eigh

t (k

g)

• All comparisons PIT<Non-PIT

• Only Age 4 significant (mean 0.1 kg)

• 2-way ANOVA Tag effect p = 0.043

Mean Body Weight

Age 4

ΔPOHP = 0.305*Ln(SARS) + 1.088

R2 = 0.781, p<0.01

SARS (Non-PIT)

ΔP

OH

P L

ength

Du

e to

PIT

(cm

) 0.0

-0.2

-0.4

-0.6

-0.8

-1.0

-1.2

0.000 0.005 0.010 0.015 0.020 0.025

Reduction in POHP length due to PIT tag effects vs

SARS of Non-PIT tagged fish

There was no significant correlation between SARS of

Non-PIT tagged fish and PIT tag loss rates

PIT tag loss rate = 18.884 - (58.567 * NPT SARS)

R2 = 0.104, p=0.597

0

5

10

15

20

0.000 0.005 0.010 0.015 0.020 0.025

Non-PIT tagged SAR survival

PIT

ta

g l

oss

ra

tes

(%)

Conclusions

• Bingham Creek Hatchery Fall chinook

– PIT tag loss was <2% over the 3 months post-tagging

– PIT tag induced mortality averaged 23.3% post-

release and was significantly higher than in the two

Control groups

Conclusions

• Yakima River Hatchery Spring Chinook

– PIT tagged Adults were smaller; increased effect with lower SARS

– No difference in return timing to the upper Yakima River

– Mean PIT tag loss was 18%; stable over years

– PIT tag loss occurred within the first 6 months after release and did

not increase with age

– Brood year SARS were underestimated by up to 45% due to a

combination of tag loss and induced mortality; averaging 25%

– Estimated PIT tag induced mortality was as great 33% and averaged

10% over all brood years

Big Picture Points

• PIT tags can have a significant impact on study fish

• Different species, basins and ecological circumstances will result in different tag effects

• Design studies to include double-tagged fish to assess tag loss

• Include non-PIT tagged fish to assess PIT tag effects on survival

QUESTIONS?

Brood-

yearRcwt pitrP̂ Rpit cwtrP̂ Rpit,cwt R̂ R̂ - R

Total

recoveries

1997 112 0.163

(+0.002)

26 0.043

(+0.001)

574 716.9 5.1 7004

1998 95 0.198

(+0.004)

30 0.073

(+0.003)

384 517.0 7.4 7678

1999 4 0.174

(+0.022)

3 0.136

(+0.020)

19 26.5 0.6 724

2000 37 0.197

(+0.002)

1 0.007

(+<0.001)

151 189.3 0.2 4160

2001 17 0.187

(+0.009)

6 0.075

(+0.006)

74 98.4 1.4 887

Total 265 66 1202 20453

Mean

(Bootstap

95% CI)

0.184

(+0.012)

0.067

(+0.032)